After the doctor has diagnosed a given medical situation (illness, accident, hemorrhage, etc.), it may be necessary to treat it by administering to the patient a suitable product: a medicament, blood, etc. The invention relates to an administration via injection, in particular via a perfusion.
As is known, perfusion into a peripheral vein is set up in the following manner.
After having located a peripheral vein, the patient's skin is pierced using a needle covered with a catheter (such a device is known under the brand Cathlon®). Once the needle is positioned in a vein, the distal end of the catheter is pushed into the vein, the needle is removed, and the proximal end of the catheter is fastened to the patient's skin using a sterile dressing. Various diameters of catheter exist, and are generally expressed in terms of gauge (G). The diameter of the catheter used depends on the condition of the patient, on the operation to be carried out (sample collection or injection) and on the age of the patient. For example, the following catheters will be chosen: 22 to 24 gauge for newborns, 22 gauge for children from 1 month to 3 years old, 20 gauge for older children. For adults, it will be possible to choose catheters from 18 gauge (i.e. an external diameter of 1.1 mm to 1.3 mm) up to 14 gauge (i.e. an external diameter of 1.8 to 2.2 mm).
A table showing the connection between the “gauge” unit and the metric system is given below:
gauge (internal diameterof the needle)External diameter (mm)24 G0.6 to 0.722 G0.7 to 0.920 G0.9 to 1.118 G1.1 to 1.316 G1.5 to 1.814 G1.8 to 2.2
The catheter bears, at its proximal end, a connection device, for example of Luer lock type, and at its distal end perfusion tubing. This connection device may be such that when the catheter is not connected, its proximal end is closed and the blood cannot escape.
In general, after connecting the catheter, a safety loop is produced with the tubing that is fastened to the patient's skin with tape. This safety loop prevents the catheter from being immediately pulled out in case of tension on the perfusion tubing.
The proximal end of the tubing is in fluid communication with an expansion vessel connected to a rigid or flexible bag of perfusion product attached to a pole. The latter must be high enough relative to the patient's catheter so that the perfusion product flows by simple gravity toward the catheter then the vascular system of the patient.
The tubing comprises, preferably, a toothed wheel for controlling the flow rate of perfusion, or other control system.
Before letting the product flow via perfusion, it is essential to carry out a final compatibility check between the treatment previously prescribed by the doctor and the treatment that is about to be given to the patient. This check makes it possible to verify that the product indeed corresponds to the diagnosed medical situation and/or that it will be well tolerated by the patient.
For example, for blood transfusion, when a doctor has prescribed a transfusion for a patient of given blood group, the nurse must ensure that the blood bags that he/she has are compatible with the patient's blood group since there can be errors in allocating blood bags or in the identification of the patient or of the blood bags.
Conventionally, the nurse uses card stock impregnated with anti-A and anti-B reagent on which he/she deposits blood from the patient (obtained by pricking the end of the finger or a vein) and blood from a sample from the transfusion bag. For this purpose, the transfusion bags have a main container for the transfusion, and secondary sampling containers, that can be separated from the main container.
The nurse then assesses the presence of agglutinates on the card stock and compares the reactions obtained with the patient's blood and with the blood from the sample. The nurse must then apply the compatibility rules that he/she has learnt in order to interpret the results of the test. This interpretation may be tricky, especially in the presence of weak antigens or in certain pathologies.
Thus, it has been noticed that there are still many errors due to fatigue, due to an emergency situation or to inattention, during the interpretation of these tests, but also during the setting up of the transfusion bag and, more generally, of the second perfusion.
In particular, it has been noticed that only too often the product of the second perfusion is not that which had been prescribed by the doctor.
These errors may simply slow down the patient's recovery, for example when the dosage of the perfused product is lower than that which is prescribed by the doctor in order to cure the patient. They may also lead to the death of the patient, for example when the blood transfused is incompatible with the patient's blood group (A, B, AB or O), or when the patient is allergic to the antibiotic perfused whereas the patient was not allergic to the antibiotic initially prescribed.
Handling errors may also occur that are dangerous for the nursing staff if there is direct exposure to the patient's blood.
To overcome this problem, the current solutions aim to ensure that the information written on the transfusion bag and information written on a support borne by the patient agree. These technologies mainly consist of bar code or RFID chip control systems. However, handling errors still exist, especially due to perfusion bag labeling errors or patient identification errors.